1. Technical Field
The present disclosure relates to technology of manufacturing printed circuit boards (PCBs), and particularly to a method for manufacturing a IC substrate.
2. Description of Related Art
In current, there are two main IC substrate types: one having a core and the other one without a core (i.e. coreless one). However, an IC substrate having a core is thicker, and an IC substrate without a core is easy to be warped because of lacking a rigid support.
A normal method for manufacturing an IC substrate includes the following steps: taking a rigid copper clad laminate (e.g. fiberglass resin) as a core and forming a first inner wiring layer and a second inner wiring layer; machine drilling, plating through hole, and filling material in the plating through hole and so on, such that the first inner wiring layer is electrically connected to the second inner wiring layer; laminating a adhesive sheet and a copper foil onto the core to build the core up, thereby forming a build up wiring. With a development of technology, a thick of the core reaches to 100 micrometers. However, under the method for manufacturing the IC substrate described above, it is impossible to make the IC substrate thinner, and it is convenient to use the IC substrate to a semiconductor package. Another method for manufacturing a IC substrate includes the following steps: instead of using a copper clad laminate as a core, using a adhesive sheet and a copper foil to manufacturing a build up wiring, forming a conductive via in the adhesive sheet, and forming a wiring layer on the adhesive sheet, the wiring layer being electrically connected to the conductive via; and repeating the above steps in the above method for manufacturing the IC substrate. The method without using the copper clad laminate as a core can reduce the thickness of the IC substrate. However, this method is a single-sided build up method, and a IC substrate wrap is easy to occur. A plurality of IC substrate is thus scraped.
What is needed therefore is a method for manufacturing a multilayer printed circuit board to overcome the described limitations.